A restart control system includes a rotational angle estimation unit that estimates a rotating electrical machine's rotational angle in a state wherein an internal-combustion engine's rotational speed detected by a rotational speed detection unit is higher than an estimation threshold and configured not to estimate rotating electrical machine's rotational angle in a state wherein internal-combustion engine's rotational speed is lower than estimation threshold; a rotating electrical machine control unit increases internal-combustion engine's rotational speed by rotating electrical machine under condition where predetermined restart conditions are satisfied and rotating electrical machine's rotational angle is estimated by rotational angle estimation unit, thereby restarting the internal-combustion engine; and a starter motor control unit starts driving of a starter motor under a condition where predetermined restart conditions are satisfied and internal-combustion engine's rotational speed falls below a predetermined rotational speed set lower than estimation threshold, thereby increasing internal-combustion engine's rotational speed to estimation threshold.

A starter for an internal combustion engine includes a multi-phase brushless electric motor, a controller and an inverter. A method for controlling the starter includes determining initial current commands for operating the electric motor in response to an activation command. Electrical current supplied to the electric motor and a rotational position of an output member of the electric motor are monitored. The electrical current is monitored directly without an intervening current prediction step. Interim voltage commands are determined based upon the initial current commands and the monitored currents, and final voltage commands are determined by subjecting the interim voltage commands to voltage limits. A rotational position compensation term is determined based upon the rotational position and rotational speed of the electric motor, and operation of the inverter is controlled to control the electric motor based upon the final voltage commands and the rotational position compensation term.

A restart control system includes a rotational angle estimation unit that estimates a rotating electrical machine's rotational angle in a state wherein an internal-combustion engine's rotational speed detected by a rotational speed detection unit is higher than an estimation threshold and configured not to estimate rotating electrical machine's rotational angle in a state wherein internal-combustion engine's rotational speed is lower than estimation threshold; a rotating electrical machine control unit increases internal-combustion engine's rotational speed by rotating electrical machine under condition where predetermined restart conditions are satisfied and rotating electrical machine's rotational angle is estimated by rotational angle estimation unit, thereby restarting the internal-combustion engine; and a starter motor control unit starts driving of a starter motor under a condition where predetermined restart conditions are satisfied and internal-combustion engine's rotational speed falls below a predetermined rotational speed set lower than estimation threshold, thereby increasing internal-combustion engine's rotational speed to estimation threshold.

A starter for an internal combustion engine includes a multi-phase brushless electric motor, a controller and an inverter. A method for controlling the starter includes determining initial current commands for operating the electric motor in response to an activation command. Electrical current supplied to the electric motor and a rotational position of an output member of the electric motor are monitored. The electrical current is monitored directly without an intervening current prediction step. Interim voltage commands are determined based upon the initial current commands and the monitored currents, and final voltage commands are determined by subjecting the interim voltage commands to voltage limits. A rotational position compensation term is determined based upon the rotational position and rotational speed of the electric motor, and operation of the inverter is controlled to control the electric motor based upon the final voltage commands and the rotational position compensation term.

Provided is a system of carrying out engagement of a pinion and a ring gear at optimal timing and suppressing a bite-in sound, in a vehicle including an idle stop system. In a vehicle control device including an automatic stop unit which automatically stops an engine on the basis of an operating state of a vehicle; an automatic start unit which controls a starter during a period until the engine completely stops after the automatic stop unit executes the automatic stop of the engine, and restarts the engine; and an engine rotation detection unit which detects or operates a crank phase or a rotation number of the engine, the automatic start unit determines a control command of the starter at an interval shorter than an update interval of a signal of the engine rotation detection unit.